Add liquid first. Pour almond milk into the blender. Adding liquid first prevents ingredients from sticking to the bottom and helps blades move freely.
Add soft ingredients. Add Greek yogurt, almond butter, and protein powder before frozen items.
Add berries and flaxseed. Add the mixed berries (frozen or fresh), ground flaxseed, and vanilla extract.
Add ice if needed. If using fresh berries, add 3-4 ice cubes for a cold, thick consistency. Skip ice if using frozen berries.
Blend until smooth. Start on low speed and gradually increase to high. Blend for 45-60 seconds until completely smooth with no chunks.
Adjust consistency. Too thick? Add more almond milk, 2 tablespoons at a time. Too thin? Add more ice or a few more frozen berries.
Serve immediately. Pour into a large glass. Smoothies are best consumed fresh as the protein powder can thicken and the mixture can separate if left sitting.